Amikacin Dosing in ATT-Induced Hepatitis
In patients with ATT-induced hepatitis, amikacin requires no dose adjustment for hepatic impairment alone, but if renal function is impaired, reduce the dosing frequency to 12-15 mg/kg two to three times per week while maintaining the full dose per administration. 1
Standard Dosing in Hepatic Disease
- No precautions or dose adjustments are necessary for hepatic disease alone when using amikacin. 1
- The standard adult dose remains 15 mg/kg per day (maximum 1.0 g/day) intramuscular or intravenous, initially given as a single daily dose 5-7 days per week. 1
- For patients greater than 59 years of age, reduce the dose to 10 mg/kg per day (750 mg maximum). 1
Critical Monitoring in Hepatic Disease
Patients with severe hepatic disease require close renal function monitoring because they are predisposed to hepato-renal syndrome and may be at greater risk for nephrotoxicity from amikacin. 1
- Monitor renal function closely throughout treatment, as chronic liver disease patients with hypoalbuminemia and hyperbilirubinemia face increased risk of amikacin nephrotoxicity. 2
- Serum drug concentration measurements should be obtained routinely to avoid toxicity. 1
- Monthly monitoring for auditory or vestibular symptoms is essential, with audiogram and vestibular testing repeated if eighth nerve toxicity symptoms develop. 1
Dosing Adjustments for Concurrent Renal Impairment
If renal function becomes impaired (common in ATT-induced hepatitis patients):
- Reduce dosing frequency to two or three times per week, but maintain the dose at 12-15 mg/kg per administration to preserve the concentration-dependent bactericidal effect. 1
- Smaller doses may reduce drug efficacy and should be avoided. 1
- Dosing adjustments are essential because amikacin clearance is almost exclusively by the kidney. 1
- For hemodialysis patients, administer the drug after dialysis to facilitate directly observed therapy and avoid premature drug removal. 1
Nephrotoxicity Risk Factors
- Renal impairment occurs in 8.7% of patients receiving amikacin, with higher frequency in those with initially elevated creatinine levels, larger total doses, and concurrent nephrotoxic agents. 1
- In patients without risk factors, nephrotoxicity occurs in 3.4% of cases. 1
- Hypoalbuminemia at treatment initiation and end, plus elevated bilirubin at treatment end, are specific risk factors in chronic liver disease patients. 2
Common Pitfalls to Avoid
- Do not reduce the per-dose amount in renal insufficiency—only extend the dosing interval while maintaining 12-15 mg/kg per dose. 1
- Do not assume hepatic impairment alone requires dose reduction—amikacin undergoes renal elimination, not hepatic metabolism. 1
- Avoid concurrent use with other nephrotoxic agents whenever possible, as this significantly increases nephrotoxicity risk. 1
- Do not use fixed dosing schedules; calculate dosage based on actual body weight for each patient. 3